1. Field of the Invention
The invention relates to the field of power electronics. It is based on a high-speed disconnector using semiconductor technology, in accordance with the preamble to the first claim, particularly suitable for uninterruptible power supplies for a load supplied by an AC power supply system. A disconnector of this generic type is described in the French Patent Application FR 2 666 941 A1, for example.
2. Discussion of Background
Disconnectors of this generic type are used for decoupling the load from a supplying AC power supply system. They can be used, in particular, for uninterruptible power supplies. Uninterruptible power supplies have an auxiliary voltage source which can be coupled to the load by coupling means after the load has been disconnected from the AC power supply system. The auxiliary voltage source can, by way of example, comprise a battery, whose DC voltage is converted to an AC voltage by means of a converter, a diesel unit or a rotating system which utilizes the kinetic energy of a generator.
High-speed uninterruptible power supplies having reaction times in the millisecond range are generally used, in particular, for sensitive loads such as computer systems or electronic apparatuses in hospitals. This makes it possible to ensure that all types of transient disruptions and brief voltage dips can be bridged, so that the load always has access to an uninterrupted AC voltage. The power requirement of such loads does not normally exceed a few tens of kW. Devices having power transistors or IGBTs can therefore be used as disconnectors.
Nowadays, solutions using rotary converters are preferred for sensitive loads with a relatively high power requirement (e.g. 0.5-2 MW). In this case, the kinetic energy of a generator is used to support ms-duration dips. If the disruption lasts for a longer time, a further inertial mass is connected by means of a dynamic coupling. In addition, a diesel unit can be started up and connected, in order to cover minute-long disruptions as well. Such rotating systems have been prior art for years and have proved themselves in principle. However, on account of the complex mechanisms and the occasional need for continuous operation of the equipment, they require a high level of maintenance and have significant losses. Furthermore, a number of systems need to be connected in parallel for powers greater than 2 MW.
For economic and technical reasons, it has not been possible up to now to transfer known electronic circuits to high-power applications.